Despite laboratory testing, the performance impact of a new web application feature may be difficult to predict prior to release. One approach to tracking performance of a new web application feature is to focus on the impact that feature may have on servers that provide the web application. However, the impact that the new feature may have on client devices is entirely ignored.
One approach to monitoring performance degradation is to compare overall performance data as observed before and after general release of a new feature. However, this approach is not well suited to sophisticated deployment techniques. Additionally, this approach would be unaware that some application users may be served a variant of an application while other simultaneous users are not served the variant.
A result of such an approach is that observation of performance degradation of a not widely used variant may be lost within statistical measurements of a greater audience of a generally available application. An inability to isolate variant performance is exacerbated by the possibility of a separate variant for each of multiple new features.